Dscult interrupting device



W. E. PAUL CIRUIT lINTERRUPTING DEVICE Nov. 24. 1931.

WLLLLam E. Paul.,

bij

HLS Attorney Reissued Nov. 224,Y

' UNITED STATESv Pla-TEIWP OFFICE u E. ram., or sommari?, maw xonir, Assrcnon ro eliminar. mera:

originel 1re. Luau?, mea 1111114.41531, aerial` ne. ssaosa, mea september 20,1929.

reime mea oeteber a, 1931. serien ne. seem.

My invention Vrelatesto a, circuit interrupting device, and moreparticularly to contact structure of lthe {luid-breakl type wherein pressure developed byan arc iiseiective to f assist in interrupting the current traversing said contact structure.

" The interruption of alternating currents,

.particularly power currents of considerable magnitude, has been attianded' by difliculty,

lo some of the reasons being that-the separating contacts may open, at any particular. time,

- as when the current is increasing in value, thereby increasing the persistence ofthe arc, and that a cooling stream or blast of insulating fluid is not immediately available across the'contacts so separated even in the event that the separation' is elected at a decreasing or zero current value,

An object of my invention is the provision of an iin roved circuit interrupter of the iluid-breag type wherein pressure generated by arcing is utilized to cause circuit interruption.

A further object of my invention is the provision of means associated with the contacts of a fluid-break switch for eii'ecting fseparation of cooperating contacts' to interrupt an alternating current at substantially the point of zero current value, and for eifecting a blast or rapid flow of insulating fluid across the separating contacts in response to the pressuredeveloped by an initial or separat arc. f

A further object of `my invention is the provision of arc-extinguishing means incorporated in a fluid-break switch wherein initial or opening movement of the switch is effective to produce anarc, the pressure developed by the same being regulated and/or directed soas to move a contact member towards an open circuit position, and to force a body of the insulating fluid 'between the aforesaid contact member and its cooperating contact. Y 'A y My invention will be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty which characterize my invention Vwill be pointed out 'with particularity lin the comm, A oonrona'rrox or NEW You.. n

cmcm'r mrmUrmG mivrcn Application for claims annexed to and forming a part of this speeiication. A

Referring to the accompanying drawings, Fig. 1 is an elevational view, partly section, of circuit interrupting apparatus embodying my invention, and Fig. 2 is a modication of the lstructure shown -in Fig. 1.

As illustrated in Fig. 1,l the contact structure of the switch is immersed in an insulating liquid 1, such as oil for example, and compnses the usual conductor bushings 2 and 3 within which the conductor studs 4 and 5 are disposed. At the lower ends of the bushings 2 and 3 are mounted housing structures 5 and 6. for the contact structure. The usual bridging member 7 actuated by an operating rod 8 carries at its opposite ends the movable contact members, or studs, 9 and 10 which are adapted to extend through the lower part of the respective housing structures.

The housing structures as illustrated in the present instance are ,composed of a number of sections of insulating material clamped or secured together in any suitable manner, and referring more particularly to the housing structure 5 in section, there is provided a lower pressure chamber 11 into which the contactmg end of the stud 9 extends through the opening 12 in the lower wall of the housing. A member 13 comprising the upper wall of the chamber is provided with an opening 14 through which one end of a plunger-like conducting member 15 extends so as to be capable of contacting at one end with the stud 9. The member 15 1s provided with a .piston lelement 16 for a purpose hereinafter describedx and is normally resiliently biased upwardly to the position shown, as by a spring 17 seated at its lower end on the wall member 13. The member 13 includesa verticall extending portion which together with a wall member'18 forms a passage 19 leading' from the vrpressure chamber to the upper working v side of the piston element 16; The plunger member 15 extends through'and is guided by the member 18 for longitudinal reciprocal movement.I A 'suitable vent opening 20`may be provided in the side wall of the housing communicating with the lower side of the piston element in order that the movement ofV 1( Y '19 communication with the pressure chamber 11v the member may be regulated by thespring 17. Y Cooperating contact structure is mounted in the `upper part of the housing and comprises a contact element 21 adapted to be controlled as hereinafter ,described for contacting with the upper end of the conducting member 15.V The point of contact of these members is located within a nozzle-like passage 22 forming an arcing chute and in direct through the vertically extending passage 23.

The upper side of the arcing chute comprises a wall member 24 havinfg an opening 25 within which the contact e ement 21 may freely move.

The contact element 21 forms a part of Va conducting loop comprising the conducting portion 26 connected to the lower end of the stud 4 and a conducting lever 27 connected for relative movement, as by the pivot 28, to

the portion 26. The contact element 21 which is mounted at the end of member 27 is resiliently biased, as by a. spring 29, towards the compressed position of the loop, i. e., sothat.

the members 26 and 27 are substantially parallel with each other. A resilient member, as the spring 30, may be interposed between members 26 and 27 to serve as shock absorbing or buffer means when the contacting member15 moves upwardly into engagement with thecontact element 21. l

v As is well known, the magnetic forces of current traversing an open loop tend to cause expansion of the loop, or in other words, current iiowing'in opposite directions in parallel conductors produces magnetic forces j tending to repelthe conductors from each other. In the present instance, the current 'in flowing through the conductor stud 4 and the members 26 ,and 27to the contact element- 21,.` tends to repel the member 27 in a counterclockwise direction about its pivot. This repulsion, however, is resisted by the tension spring v29 which may be suitablyv insulated, or may be of high resistance material, so that it will not shunt an appreciable amount of current. The tension of the spring 29 may be suitably adjusted so that it 1s effective by itself to maintain the contact element y21 in the position illustrated during minimum values of the current but for higher values of the current it will be overcome by the repellent'magnetic forces of the loop.

The Toperation of the device is as fol ows: With the elements in the positions illustrated in the drawings representative of the closed circuit position of the switch, actuation of the rod 8 to lower the movable conltact members results in an immediate separation of the lower or pressure generating set of contacts, i. e.,-contact9 and the lower contacting portion of the member 15. Since operating currents at comparatively high voltages are involved, an initial are w11l be fdrawn between the contact faces so separated which will immediately develop a pressure within the chamber 11 due to the well known action of the arc on an insulating Huid such as oil. This pressure is communicated at once through the passage 19 to the working side of the piston element 16 to produca differential pressure on member 15 and to cause depression of the same, the extent of depression being governed to a certain extent by the s rlng 17. Itwill be apparent that immedia ely lupon formation of the initial arc, the contactmg member 15 is moved by the presl sure so created so' as to follow the movable contact 9 and to prevent the arc from rapidly increasingin length. In other words, since the gaseous pressure developed by the arc is dependent among other things on the a'rc length, the regulation of -the arc length inV the manner above described likewise serves to regulate the pressure developed within the y chamber 11 and to prevent it from attaining dangerous values. The arc is therefore automa-tically regulated by its own pressure.

The ressure developed within the chamber 11 1s likewise communicated by way of the vertical passage 23 to the arc chute through which it tends to force a cooling stream or blast of the insulating liquid. As the contacting'member 15 moves downwardly to separate the contacts 15 and 21 in response to the pressure developed by the initial arc, the contacting element 21 tends to remain in following engagement therewith until the spring 29 is effective to overcome the repulsion of the magnetic forces in the above described loop. When the current in the loo is at the maximum part ofthe c cle it wiH be apparent that interruption at t at point is most diicult, and accordlngly the contact element 21` is maintained in engagement with its coacting contact surface. When, ,how-

ever, the current decreases to nea' its mimmum value the spring 29 is effective to overcome the magnetic forces of the lpop, and accordingly 'sna s the contact element 21 away from themem er 15 at substantially the very time when interruption of the currentis most easily accomplished. Concurrently with separation of the set of current interrupting contacts A15, 21, the pressure developed within chamber 11 is effective to shoot a stream of the oil across the -break so formed. This serves to interpose a fresh cooling dielectric between the contacting surfaces so as to prevent appreciable dissociation of gases and consequent formation of an arc.

Interruption of the current serves to re store the plunger 15 to its position illustrated in the drawings in which' it is biased into good contacting engagement with the contact 21. Closure of the switch is thereupon effected by simply moving the bridging member 7 by its operating rod upwardly to cause engagement of the contacts 9 and 10 with the lower conv -tacting surfaces of the corresponding plunger the passage 23, substantially sealing the same,

and is4 movable between the upper and lower limiting shoulders .41 and 42 respectively.

- Pressure developed within the chamber 11 forces the piston upwardly to project insulatin fluid between the separating contacts.A en the pressure in chamber 11 has diminished, the piston is returned by gravity `or-suitable biasing means to its lower position :as illustrated. By this construction the hot gases formed by the initial arc-are kept away from the contacts which are to interrupt the current, thereby maintaining high dielectric strength between the same during separation thereof to prevent formation of an arc.

It shall be understood that my invention is not limited to the speciiic details of construction as illustrated and described, and b way of example, the conducting loop of whiclyil the contact 21 forms a part, may comprise any suitable flexible construction capable of operating in the manner described.

What I claim as new and desire to secure y Letters Ratent of the United States is:

' 1. Circuit interrupting apparatus of the duid-break type comprising relatively movable contacts,'means for effecting in response to opening movement of one of said contacts a break for drawing an initial arc, and means for subsequently effecting opening movement of another of said contacts at substantially a minimum current value to .-form a second break, the pressure developed by the initial arc being eective to force a stream of cooling insulating fluid across the last-named break. y

2.- Circuit interrupting apparatus of the liquid-break type comprising a movable contact, aconductin'g member normally in engagement therewith, said contact aand conducting member being immersed in `an insulatingeliquid, means resiliently biasing said mem r away from said contact member, and means for directing the pressure developed by the aro formed upon separation of said contact` and said member to cause How of insulating liquid across a second are in series therewith to interrupt the circuit, the aforesaid pressure likewise acting .on said conducting member against said resilient means to regulate the length of the firstnamed arc`.

3. In a {luid-break switch, contact struc- -ture comprising a movable contact, a movable conducting member including a differential piston normally in engagement therewith whereby initial opening 'movement of the switch is eiective to draw anarc between said contact and the conducting-memberv within a pressure chamber, and means for directing the pressure developed by said arc to cause movement of said member towards said contact to prevent excessive lengthening of the arc and to elect fiowof insulating iuid across another arc in series with said iirstnamed arc to interruptthe circuit.

4. In a fluid-break switch, contact structure comprisingrelatively movable contacts a movable conducting member'interposedv tween said contacts whereby initial opening d movement of the switch is effective todraw an initial arc between one of said contacts and the conducting member, said-other contact including means for separatin the same from the conducting member at a ecreasing or zero current value, and means for utilizing the pressure developed by the initial arc to eifect a blast of insulating fluid across the break formed between the last-named contact and the conducting member.

`5. Circuit interrupting apparatus of the fluid-break type comprising a movable contact, a contact pivotally Jmounted forming part of a loop traversed by the current to be interrupted, a spring biasing said contact towards compressed position of the loop in opposition to the ma etic forces of said current, a plunger havlng a piston member interposed between said contacts, said plunger normally resiliently biased towards said piv oted contact, and a pressure chamber within which separation ,of said movable contact and plunger Amay take place tocause an initial arc whereby the pressure so developed is effective to move said plunger away from the vpivoted contact and to direct a stream of inelement forming part of a loop .traversed by said current, means biasing said element towards the compressed position of the loop, a conducting member interposed between said movable contact and contact element, and

means for utilizing the pressure developed by an arc between the movable contact and conducting member upon initial opening movement oi the switch for moving the conducting member away from lthe contact element minimum current value comprising a contact and for directing a flow of insulating iuid between the same upon separation thereof, the magnetic forces of the current traversing the aforesaid loop tending to expand the sane and to cause the contact element to remain in following engagement with the conducting memberuntil overcome by said biasingvmeans during minimum Current value.

7. lThe combination with a Huid-break.

' switch comprising a movable contact, of

loop in opposition to the magnetic forces of l member in opposition to its biasin current traversing the same a conducting `plember normally resiliently iased into conacting engagement with said element and interposed between the same and the movable contact, and means for utilizing the pressure developed by the arc drawn between the novable contact and conducting member in response to initial opening movement of the switch for moving the `conducting means away. from the vcontact element an for directmg a blast of coolinginsulating iluid across the arc caused bythe separation thereof, said element remaining in following engagement with the conducting member, until retracted by said spring during a minimum current value.

8. Inv a Huid-break switch, arc-extinguishing means comprising a movable contact a conducting member in engagement therewlth in the closed position of the switch, a contact element coacting with said member, and a pressure chamber within which se aration of said movable contact and mem r may take place to form an arc, the ressure developed by said arc being effective to move said member away from'the contact element and towards the movable contact thereby limiting the length of the aforesaid arc and e providingsubstantially constant pressure for directing a blast. of insulating fluid between sbaejd contact element and conducting memr. 9. Circuit interrupting apparatus comprising a housing structure, a plunger-like conducting member mounted for reciprocal movement within said housing contactsl'between whieheeid member is ,die d, seid housing forming a ressure cham r within which separation o one of said contacts and Y. @said member ma take place, and an arcing 5. chute within whlch separation of said member and the other of said contacts may take e place, said ressure chamber connected by passages wit said plunger member and arcchute for causing in response tol pressure developed b .an arc within said chamber withdrawal o said member from the last-named contact and a blast of insulating fluid between the same through saidarcin chute.

10. The combination with' a uid-break switchyof current interrupting means comprising means for forming an initial'arc in to intial o ning movement of the' switch,means for e ecting separation of contact members of said switch at substantially. a current value, and a pressure arcing at sai chamber within which said-initial arc'is formed whereby the ressure develo thereby is utilized to project insulating `uid between said se arating contact members.

11. The combination with a {luid-break switch, of current interrupting means comprising means for forming an intial arc in pressures within said switch are recluded. y

uid-break 12. The combination with a switch, of current interrupting means comprising means for forming an initial arcv in response to initial opening movement of the switch, a ressure chamber in which said `arc is form ,contact members adapted to be separated subsequentto formation of said arc, and a floating piston member interposed between said pressure chamber and contactmembers whereby the pressure developed by the initial arc is eiiective to movesaid piston and project insulating uid between the separating contact members while precluding gas formed. b said arc.

13. A circult interrupter of the fluid-break type comprising means forming a pressure generating arc in an insulating liquid, a pairv of circuit interrupting contacts, and means utilizing the ressure generated by said arc se aratm said contacts forcing a jet of inl suy ating quid between the same andextin-` guishing arcmg. l .Y V 14. A circuit interrupter of the fluid-break type comprising two sets of contacts connected 1n series immersed in an insulatin liquid, one set of contacts forming an initia pressure generating arc in response to circuit openm movement, the pressure generated by said Aare forcing apart the other set of contacts causing a blast of insulating liquid between the same extinguishing arcing.

15. A circuit interrupter of the fluid-break type comprising contacts immersed in an insulating lituid, the pressure generated by contacts causing interruption of the circuit, and means nsive to said pressure regulating the lengt of said arc.

16. A circuit interrupter of the fluid-break' .type comprising a plurality offsets of con-` tacts immersed 1n an insulating liquid, one set of contacts forming a ressure generating are, and means responsive to. the pressure generated limiting the length osaid arc,

the pressure generated by said arc interruptin the circuit at another set of contacts.

7. A circuit interruptor of the fluid-break type oo mp'rxsing two sets of contacts conectedmsenes immersedin'an liquid, pneof said sets forming la pressure generating are Acausing separation of the other set of contacts and forcing a. jet of insulating liquid therebetween, and means re- 5 s onsive to' said .pressure generated limiting t e length of said 18. A circuit interrupter of the fluid-break type comprising contact structure immersed in an insulating liquid, means forming a 10 A' pressure generating arc within said liquid, andmeans responsive to the pressure generated'thereby limiting the length of said are, said pressure causing interruption of f the circuit at coacting contacts. '15 In witness whereof, I lhave hereunto set m hand. 4 Y v y y WILLIAME. PAUL. 

